Characterization of the nature of the disulfide bonds in the higher hydrodynamic volume forms. Reduction and reoxidation of the derivative of lysozyme containing carboxymethylated cystine residues at position 6 and 127. Crystallization and X-ray diffraction studies of the above derivatives. Carboxypeptidase and aminopeptidase digestion of the derivative carboxymethylated at cysteine residues 6 and 127 in an attempt to get a complementing system to explore further the folding process of reduced lysozyme.